Effect of hypotension and anaemia on perioperative kidney function is time critical

BACKGROUND Peri-operative acute kidney injury is a prevalent and serious complication in surgical patients, significantly associated with increased mortality and long-term healthcare burdens. Understanding the multifaceted aetiologies, such as haemodynamic instability and anaemia, is crucial for devising effective prevention strategies. However, there is a lack of comprehensive analysis on the independent and dose-dependent effects of peri-operative hypotension and anaemia as predictors of severe acute kidney injury outcomes in diverse surgical populations. OBJECTIVE The aim of this study was to show that cumulative exposure to both hypotension and anaemia is independently associated with the development of severe acute kidney injury. DESIGN In a retrospective cohort study, the dose-dependent effects of low blood pressure and decreased haemoglobin levels on severe acute kidney injury have been estimated. SETTING Tertiary referral centre. PATIENTS This study included 75 183 patients with complete electronic medical records between 01 January 2015 and 30 June 2025 that underwent anaesthetist assisted procedures. MAIN OUTCOME MEASURES Peri-operative severe acute kidney injury (KDIGO stage 3) RESULTS Both severe hypotension (MAP <50 mmHg) and severe anaemia (haemoglobin <7.5 g dl −1 ) substantially increase the risk of severe acute kidney injury. Specifically, each additional minute of severe hypotension and each day of severe anaemia exposure incrementally elevated the hazard for KDIGO stage 3 acute kidney injury, even after adjusting for confounders, hazard ratio=1.01 (95% CI 1.01 to 1.01), and hazard ratio=1.06 (95% CI 1.03 to 1.09), respectively. CONCLUSIONS These findings emphasise the importance of both the duration and severity of haemodynamic and oxygenation-related insults in increasing the risk of severe kidney injury for patients. This suggests a need for heightened vigilance and tailored peri-operative management strategies to minimise cumulative hypotensive and anaemic episodes.